Method for evaluating contact state of connection part of electrical primary conductive loop

Abstract

The invention provides an electrical primary conductive loop connection part contact state evaluation method, which comprises the following steps of: obtaining a lap joint length L1 of a connection part to be detected, and cutting samples L2 and L3 with the same length from base materials on two sides; under the same environment condition, low-voltage large current is introduced into the to-be-tested connection part and the sample at the same time, the current is larger than or equal to 1000 A, and the voltage is smaller than or equal to 12 V; measuring and recording the temperature rise and temperature of the to-be-measured connection part and the sample part, and recording the environment temperature at the same time; calculating the relative temperature difference according to a relative temperature difference calculation formula; and evaluating the contact state of the connection part according to the relative temperature difference. According to the invention, based on measurement of multi-node temperature rise under a large current condition, accurate evaluation of the contact state of the connection part is realized by analyzing the relative temperature difference, the accuracy of evaluation of the contact state of the connection part of the electrical primary loop can be improved, reliable connection of the electrical primary loop is ensured, and equipment can stably operate for a long period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical detection, and in particular to a method for evaluating the contact state of a primary electrically conductive loop connection site. BACKGROUND

[0002] The butt joint block of the stator bar of a large hydro-generator is widely welded by brazing process. In the specific operation, first, a silver solder sheet is placed in the weld, and the welding site is inductively heated by a medium-frequency welding machine. When the silver solder sheet starts to melt, silver-copper welding wire is used for replenishment until the weld is fully filled. After welding, strict quality inspection must be carried out on the butt joint block site to ensure the welding reliability and the conductive cross section to meet the flow performance requirements. Such welding not only needs to ensure sufficient mechanical strength, but more importantly, the electrical connection surface must have excellent conductive performance.

[0003] Therefore, in actual quality control, in addition to observing the surface fullness of the weld, special attention should be paid to the uniformity and density of the internal solder filling of the lap joint surface. If the internal solder filling is uneven, it is easy to cause poor contact state of the connection site, causing the contact resistance to increase, resulting in local overheating and continuous temperature rise during power-on. In severe cases, it may cause the connection point to burn out, accelerate insulation aging, and even cause short circuit or discharge accidents, ultimately endangering the stable operation and power supply reliability of the generator set.

[0004] At present, the conventional weld detection method is difficult to comprehensively evaluate the brazing quality, especially the internal welding state lacks effective characterization. Similarly, there is no uniform standard for detecting the contact state of the primary electric loop connection site. In practice, loop resistance testing is often used as an auxiliary evaluation method, but the mainstream equipment on the market generally outputs a direct current of 100-200A, and the measurement accuracy is 0.1 μΩ. In short-distance copper bar lap joint and other application scenarios, the sensitivity and accuracy of such equipment are often insufficient to accurately judge the connection quality, thus limiting its effective application in practice. SUMMARY

[0005] The present application aims to at least solve one of the technical problems in the related art to some extent.

[0006] To this end, the first purpose of the present application is to propose a method for evaluating the contact state of a primary electrically conductive loop connection site, which can timely find and handle the hidden dangers of the primary electrically conductive loop connection site during equipment maintenance, thereby ensuring the safe and stable operation of the unit.

[0007] The second purpose of the present application is to propose an evaluation device for the contact state of a primary electrically conductive loop connection site.

[0008] To achieve the above-mentioned purpose, the first aspect of the present application proposes a method for evaluating the contact state of a primary electrically conductive loop connection site, comprising: Obtain the overlap length L1 of the connection site to be tested, and cut the same length of sample L2, L3 from both sides of the base material; Under the same environmental conditions, low-voltage large current is applied to the connection site to be tested and the sample, wherein the current is greater than or equal to 1000 A and the voltage is less than or equal to 12 V; Measure and record the temperature rise and temperature of the connection site to be tested and the sample site, and record the ambient temperature at the same time; calculate the relative temperature difference according to the calculation formula of the relative temperature difference; According to the value of the relative temperature difference, the contact state of the connection site is evaluated.

[0009] Optionally, the calculation formula of the relative temperature difference is:

[0010] In the formula: and are the temperature rise and temperature of the heating point; and are the temperature rise and temperature of the normal corresponding point; is the ambient temperature of the measured device area.

[0011] Optionally, the low-voltage large current is an alternating current with a frequency of 50 Hz ± 1 Hz.

[0012] Optionally, the current application time of the low-voltage large current is 10-60 minutes until the temperature rise of each measurement point reaches a stable state.

[0013] Optionally, the contact state of the connection site is evaluated according to the value of the relative temperature difference, including: When ≤5%, it is determined that the contact state is excellent; When 5% ≤15%, it is determined that the contact state is qualified; When >15%, it is determined that the contact state is poor.

[0014] Optionally, an infrared thermal imager is used to non-contact measure the connection site to be tested and the sample site, and the measurement area is the center area of the connection site.

[0015] Optionally, it further includes: when evaluating a plurality of connection sites in series, the same large current is applied to the plurality of connection sites at the same time to realize synchronous evaluation.

[0016] Optionally, it further includes: establishing a connection site temperature rise database, correlating and analyzing historical test data with operation fault records, and optimizing the evaluation threshold.

[0017] To achieve the above object, the second aspect of the present application provides an electrical primary conductive loop connection site contact state evaluation device, comprising: The first module is used for obtaining the overlap length L1 of the connection site to be measured, and cutting the samples L2 and L3 with the same length from the base material on both sides; The second module is used for simultaneously inputting low-voltage large current into the connection site to be measured and the sample under the same environmental condition, wherein the current is greater than or equal to 1000 A and the voltage is less than or equal to 12 V; The third module is used for measuring and recording the temperature rise and temperature of the connection site to be measured and the sample site, and recording the environmental temperature at the same time, and calculating the relative temperature difference according to the calculation formula of the relative temperature difference; The fourth module is used for evaluating the contact state of the connection site according to the value of the relative temperature difference.

[0018] To achieve the above object, the third aspect of the present application provides an electronic device, comprising a processor and a memory connected with the processor in communication; The memory stores computer execution instructions; The processor executes the computer execution instructions stored in the memory to realize the method according to any one of the first aspect.

[0019] To achieve the above object, the fourth aspect of the present application provides a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the computer execution instructions are used to realize the method according to any one of the first aspect when executed by a processor.

[0020] To achieve the above object, the fifth aspect of the present application provides a computer program product, wherein the computer program is executed by a processor to realize the method according to any one of the first aspect.

[0021] The embodiments of the present application provide at least the following beneficial effects: based on the measurement of the temperature rise of multiple nodes under the condition of large current, the relative temperature difference is analyzed to realize the accurate evaluation of the contact state of the connection site. By applying stable large current and measuring the temperature of each connection point, the relative temperature difference judgment method is combined to effectively identify the abnormal heating point, so as to judge the advantages and disadvantages of the connection state. Therefore, it can help the maintenance personnel to find and eliminate hidden dangers before the equipment is put into operation, significantly improve the reliability of the primary loop connection, and ensure the long-term safe and stable operation of the equipment.

[0022] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which: Figure 1 A flowchart of an electrical primary conductive loop connection site contact state evaluation method provided by an embodiment of the present application; Figure 2 A schematic diagram of a large current generating device of the present application; Figure 3 A schematic diagram of a temperature rise experiment operation interface of the present application; Figure 4 A schematic diagram of test data current fold line of the present application; Figure 5 A schematic diagram of test data temperature fold line of the present application. DETAILED DESCRIPTION

[0024] Embodiments of the present application are described in detail below with reference to the accompanying drawings, in which the same or similar elements or elements having the same or similar functions are denoted by the same reference numerals throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0025] Figure 1 A flowchart of an electrical primary conductive loop connection site contact state evaluation method provided by an embodiment of the present application, the method comprising the following steps: S1, obtaining the overlap length L1 of the connection site to be tested, and cutting test samples L2 and L3 of the same length on both sides of the base material.

[0026] In the embodiments of the present application, the overlap length L1 of the connection site to be tested is first obtained. The overlap length L1 refers to the length of the overlapping portion of the two base materials in the connection region, which is used to reflect the stress and bonding characteristics of the joint under welding, bonding or other connection methods. In order to ensure the comparability and accuracy of the test, test samples L2 and L3 of the same length need to be cut on the base material on both sides of the connection site before the connection site is tested. The lengths of the test samples L2 and L3 should be consistent with the overlap length L1, so as to compare the mechanical properties, microstructure and failure characteristics of the base material and the connection region in the subsequent analysis.

[0027] By measuring the overlap length L1 and cutting the base material test samples L2 and L3, it can be ensured that the connection region and the base material part have the same size basis in the subsequent experimental steps, which is beneficial to improve the repeatability of the experimental results and the comparative effectiveness of the data. This step lays the foundation for the subsequent tensile, shear or fatigue performance tests, and is an important link to ensure the experimental accuracy and comparability.

[0028] S2, under the same environmental conditions, a low-voltage large current is applied to the connection site to be tested and the test sample simultaneously, wherein the current is ≥1000A and the voltage is ≤12V.

[0029] In the embodiments of the present application, step S2 involves applying a low-voltage large current to the connection site to be tested and the test sample simultaneously under the same environmental conditions. Specifically, the applied current should be ≥1000A and the voltage should be ≤12V to simulate the current load under actual working conditions. The current is an alternating current with a frequency of 50Hz±1Hz to meet the operation standards of conventional power systems. The application time of the low-voltage large current is 10 to 60 minutes, and the specific time is adjusted according to experimental conditions and testing requirements until the temperature rise of each measurement point reaches a stable state.

[0030] The purpose of this step is to make the connection site to be tested and the test sample reach a stable temperature rise state under the same load conditions by applying a low-voltage large current, so as to better evaluate the thermal response characteristics and electrical performance of the connection site. After the temperature rise stabilizes, further measurement and analysis can be carried out to ensure the reliability and safety of the connection site and the test sample under real use conditions.

[0031] When evaluating multiple series connection sites, in order to ensure the synchronization and comparability of the test, the present embodiment also provides that a same large current is applied to multiple connection sites simultaneously, thereby achieving synchronous evaluation. In this way, consistent test conditions can be obtained on multiple connection sites, ensuring the reliability and consistency of the evaluation results.

[0032] S3, measure and record the temperature rise and temperature of the connection site to be tested and the test sample, and record the ambient temperature at the same time; calculate the relative temperature difference according to the calculation formula of the relative temperature difference.

[0033] In the embodiments of the present application, step S3 involves measuring and recording the temperature rise and temperature of the connection site to be tested and the test sample, and also recording the ambient temperature. During the measurement process, an infrared thermal imager is used to perform non-contact temperature measurement on the connection site to be tested and the test sample. The measurement area should be the central area of the connection site to ensure that the temperature data is representative and accurate. In order to calculate the relative temperature difference, the temperature difference is quantitatively evaluated by formula. The calculation formula of the relative temperature difference is as follows:

[0034] In the formula, and are the temperature rise and temperature of the heating point; and are the temperature rise and temperature of the normal corresponding point; is the ambient temperature of the measured device area.

[0035] This calculation formula quantifies the difference between the temperature rise of the connection point and the ambient temperature, thereby evaluating the thermal response characteristics of the connection point under low-voltage, high-current conditions. The temperature change reflects the current load and thermal performance of the connection point, providing necessary information for subsequent analysis. Furthermore, the non-contact measurement method of the infrared thermal imager ensures accuracy and safety during the experiment, avoiding the potential heat effects or measurement errors caused by direct contact.

[0036] S4, assess the contact status of the connection points based on the relative temperature difference.

[0037] In this embodiment, step S4 evaluates the contact state of the connection points based on the relative temperature difference. Relative temperature difference The size of the contact value directly reflects the thermal performance and electrical contact quality of the connection. Therefore, the contact condition of the connection is judged by the following criteria: when When the temperature rise is ≤5%, the contact condition is considered to be excellent. At this time, the temperature rise of the connection part shows a low difference, indicating that the electrical contact of the connection area is good, the heat conduction performance is normal, and the connection part can effectively distribute the current load.

[0038] When 5% < When the temperature rise is ≤15%, the contact condition is considered acceptable. At this point, the temperature rise and relative temperature difference at the connection point are moderate. Although basic connection performance can still be maintained, there may be slight contact defects or localized heat concentration. Further monitoring and optimization are needed to ensure long-term stability.

[0039] when A temperature difference greater than 15% indicates poor contact. In this case, a large relative temperature difference suggests a significant problem with the connection, which may lead to localized overheating, increased contact resistance, or potential failure risks in the connection area. Inspection and repair should be carried out as soon as possible to avoid safety hazards.

[0040] This assessment method effectively identifies the contact quality of connection points, ensuring the reliability and safety of the equipment. In practical applications, appropriate maintenance or optimization measures are taken based on different contact conditions to improve the operational stability and lifespan of the equipment.

[0041] In this embodiment, the method is not only applicable to general connection testing, but also particularly suitable for assessing the welding quality of stator bar parallel joints in large hydro-turbine generators. This method can be widely applied to various connection points, including brazed joints, copper busbar lap joints, or busbar connection points, covering the connection quality inspection of key components of hydro-turbine generators. These connection points typically bear large current loads and have stringent requirements for connection quality during operation. Therefore, accurately assessing the contact state of these connection points is crucial for ensuring the safe operation of the generator.

[0042] To further improve the accuracy and intelligence of the assessment, the embodiment also includes a step of establishing a temperature rise database for connection parts. By collecting and organizing historical test data and operational fault records, comprehensive historical reference data can be provided for the temperature rise and contact status of various connection parts. The correlation analysis of this data can not only reveal potential quality problems, but also help optimize the assessment threshold, making the assessment more accurate and enabling dynamic adjustment and optimization based on the actual conditions of different connection parts.

[0043] In the application phase, low-voltage, high-current can be achieved by... Figure 2 The high-current generating device shown herein is provided, and the high-current generating device includes: Current source: Output AC 0-3000A, voltage ≤12V, used to provide stable AC current; Temperature acquisition unit: contains at least 10 temperature measurement channels for real-time acquisition of temperature data of connection parts and samples; Control unit: Enables automatic current adjustment and automatic temperature data recording; Cooling unit: Uses forced air cooling; Protection unit: Includes overcurrent, overheat, and short circuit protection functions.

[0044] In this embodiment, the high-current generating device also includes a fully automatic temperature rise software system, which plays a core role in temperature rise testing. Its main functions include: Automatic tracking of target current and stable output: The system can accurately track the set target current and maintain a stable output, ensuring the consistency and stability of the current during the experiment.

[0045] Real-time recording of temperature data and generation of temperature rise curves: The software system can collect temperature data in real time and generate temperature rise curves in a graphical manner, providing detailed temperature change information for subsequent analysis.

[0046] Automatic calculation of relative temperature difference and output of evaluation results: The system automatically calculates and displays the relative temperature difference, and outputs the contact state evaluation results according to preset standards, reducing manual intervention and improving the efficiency and accuracy of the evaluation. In one embodiment of the present invention, the actual operation process of the high current generating device includes: In one embodiment of the present invention, the actual operation process of the high current generating device can be divided into the following steps: 1. System operation check.

[0047] Before starting the experiment, a system operation check must be performed to ensure that the equipment can operate safely and reliably. Operators should check the following in sequence: Equipment grounding: Ensure that the equipment is properly grounded to prevent safety issues caused by current leakage.

[0048] Test sample connection: Check whether the connection points or test samples are connected correctly to ensure the effectiveness of the test process.

[0049] Environmental safety: Ensure the safety of the testing environment and avoid unnecessary accidents.

[0050] System Reset: Start the system and wait for the system to complete the reset operation. Confirm that the zero indicator lights up.

[0051] 2. Communication settings.

[0052] Before each experiment, communication settings must be configured in the software to ensure a proper connection between the experimental setup and the measuring equipment. The operating steps are as follows: Source connection: Connect a high current source via software to ensure the system can correctly output the set current.

[0053] Infrared temperature measurement camera connection: Connect the infrared camera to ensure real-time temperature measurement and image acquisition.

[0054] 3. Program settings.

[0055] The system requires setting relevant source parameters. If no parameters change during the entire experiment, this setting only needs to be performed once. The operations include: Input current target: Set the target current output value to ensure it meets the experimental requirements.

[0056] Set other parameters: Set the current duration, temperature rise test area, etc., according to experimental requirements.

[0057] 4. User information management.

[0058] The system also includes user information management functions, allowing users to add and delete usernames, and set corresponding passwords and permissions to control access to experimental operations.

[0059] 5. Test complete.

[0060] After the experiment, the system was able to save the following data: Temperature curve: Records the temperature changes throughout the entire experiment.

[0061] Current curve: Records the current output for subsequent analysis.

[0062] Temperature change video: Save the temperature change video during the experiment for later playback and analysis.

[0063] Specifically, regarding the temperature rise experimental interface, such as Figure 3 As shown, first, connect to the source in the communication settings; After the communication connection is normal, the first step is to click "Read" to check the status of the source. If the source status is normal, the current increase step can be performed. If there is an abnormal status, the reset operation should be performed first. The second step is to select a working mode before each flow increase. If no working mode is selected, the default working mode will be used. The third step is to input the target output current, click the "OK" button, and then click the "Start Output" button to start the current boosting operation.

[0064] Regarding the test data, the temperature data interface displays the real-time RMS current value and the highest temperature for 10 preset temperature zones, as well as: Current curve: Displays the real-time output current curve; Temperature curve: Displays the real-time temperature curve; Live feed: Displays the real-time feed captured by the camera; Infrared image: Displays the infrared image captured by the camera; Note: The temperature measurement area of ​​the infrared camera can be manually set.

[0065] When outputting the experimental results, click "Test Complete" to output two polylines. Figure 1 The video shows the temperature rise during the experiment (the x and y step sizes in the line graph can be adjusted before saving). The line graph is shown below. Figure 4 and Figure 5 As shown.

[0066] To achieve the above embodiments, the present invention also proposes a device for evaluating the contact status of a connection point in an electrical primary conductive circuit. This device includes: The first module is used to obtain the overlap length L1 of the connection part to be tested, and to cut samples L2 and L3 of equal length from the parent material on both sides. The second module is used to simultaneously apply low-voltage high current to the connection part to be tested and the sample under the same environmental conditions, wherein the current is ≥1000A and the voltage is ≤12V. The third module is used to measure and record the temperature rise and temperature of the connection part and the sample part under test, and at the same time record the ambient temperature; calculate the relative temperature difference according to the formula for calculating the relative temperature difference. The fourth module is used to evaluate the contact status of the connection points based on the numerical value of the relative temperature difference.

[0067] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0068] To implement the above embodiments, the present invention also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer execution instructions; the processor executes the computer execution instructions stored in the memory to implement the method provided in the foregoing embodiments.

[0069] The collection, storage, use, processing, transmission, provision, and disclosure of user personal information involved in this invention all comply with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0070] It should be noted that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold outside of these legitimate uses. Furthermore, such collection / sharing should only be conducted after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes authorization of relevant user information before the user uses the function. In addition, any necessary steps must be taken to protect and safeguard access to such personal information data and ensure that others with access to personal information data comply with their privacy policies and procedures.

[0071] This invention is intended to provide implementation schemes for users to selectively prevent the use or access to personal information data. That is, this disclosure is intended to provide hardware and / or software to prevent or block access to such personal information data. Once personal information data is no longer needed, risks can be minimized by restricting data collection and deleting data. Furthermore, where applicable, such personal information can be de-identified to protect user privacy.

[0072] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0074] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of the invention pertain.

[0075] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0076] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any of the following techniques known in the art, or a combination thereof: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0077] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0078] Furthermore, the functional units in the various embodiments of the present invention can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0079] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0080] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0081] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for evaluating the contact state of a connection point in an electrical primary conductive circuit, characterized in that, Includes the following steps: Obtain the overlap length L1 of the connection to be tested, and cut samples L2 and L3 of equal length from the parent material on both sides; Under the same environmental conditions, a low-voltage, high-current flow is simultaneously applied to the connection part to be tested and the sample, wherein the current is ≥1000A and the voltage is ≤12V. Measure and record the temperature rise and temperature of the connection part to be tested and the sample part, and record the ambient temperature at the same time; calculate the relative temperature difference according to the formula for calculating relative temperature difference; The contact status of the connection points is assessed based on the numerical value of the relative temperature difference.

2. The method according to claim 1, characterized in that, relative temperature difference The calculation formula is: In the formula: and This refers to the temperature rise and temperature of the heating point; and This refers to the temperature rise and temperature at the corresponding normal points; The ambient temperature of the area where the device is being tested is .

3. The method according to claim 2, characterized in that, The low-voltage high-current is an alternating current with a frequency of 50Hz±1Hz.

4. The method according to claim 3, characterized in that, The low-voltage, high-current application time is 10-60 minutes until the temperature rise at each measurement point reaches a stable state.

5. The method according to claim 4, characterized in that, The contact condition of the connection points is evaluated based on the relative temperature difference, including: when When the percentage is ≤5%, the contact condition is considered excellent. When 5% < If the percentage is ≤15%, the contact condition is considered acceptable. when If the percentage is greater than 15%, it is considered a poor contact condition.

6. The method according to claim 5, characterized in that, An infrared thermal imager is used to perform non-contact measurements on the connection point and the sample, with the measurement area being the central region of the connection point.

7. The method according to claim 6, characterized in that, Also includes: When evaluating multiple connected parts in series, the same large current is applied to all connected parts simultaneously to achieve synchronous evaluation.

8. The method according to claim 7, characterized in that, Also includes: Establish a temperature rise database for connection parts, correlate historical test data with operational fault records for analysis, and optimize the evaluation threshold.

9. A device for evaluating the contact status of a connection point in an electrical primary conductive circuit, characterized in that, include: The first module is used to obtain the overlap length L1 of the connection part to be tested, and to cut samples L2 and L3 of equal length from the parent material on both sides. The second module is used to simultaneously apply low-voltage high current to the connection part to be tested and the sample under the same environmental conditions, wherein the current is ≥1000A and the voltage is ≤12V. The third module is used to measure and record the temperature rise and temperature of the connection part and the sample part under test, and at the same time record the ambient temperature; calculate the relative temperature difference according to the formula for calculating the relative temperature difference. The fourth module is used to evaluate the contact status of the connection points based on the numerical value of the relative temperature difference.

10. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-6.

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